Methods of forming magnetic shielding for a thin-film memory element

ABSTRACT

A monolithically formed ferromagnetic thin-film memory is disclosed that has local shielding on at least two sides of selected magnetic storage elements. The local shielding preferably extends along the back and side surfaces of a word line and/or digital lines of a conventional magnetic memory. In this configuration, the local shielding not only may help reduce externally generated EMI, internally generated cross-talk and other unwanted fields in the magnetic bit region, but may also help enhance the desired magnetic fields in the bit region.

RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.09/318,073, filed May 25, 1999, titled “Thin Film Memory Device HavingLocal And External Magnetic Shielding,” the disclosure of which isincorporated by reference herein in its entirety.

CROSS REFERENCE TO CO-PENDING APPLICATIONS

The present application is related to U.S. patent application Ser. No.08/993,005 filed Dec. 18, 1997, titled “HIGH DENSITY MAGNETIC MEMORYDEVICE AND METHOD OF MANUFACTURE THEREFOR,” now U.S. Pat. No. 6,048,739,issued on Apr. 11, 2000; and U.S. patent application Ser. No.08/993,009, filed Dec. 18, 1997, titled “Self-Aligned Wordline Keeperand Method of Manufacture Therefor,” now U.S. Pat. No. 5,956,267, issuedon Sep. 21, 1999, which are assigned to the assignee of the presentapplication, the disclosures of which are hereby incorporated byreference in their entireties herein.

GOVERNMENT RIGHTS

This invention was made with Government support under Contract NumberN00014-96-C-2114 awarded by NRL (Naval Research Laboratory). TheGovernment has certain rights in this invention.

BACKGROUND OF THE INVENTION

The present invention generally relates to ferromagnetic thin filmmemory devices and sensors, and more particularly, to shielding for suchthin film ferromagnetic memory devices and sensors.

Digital memories of various kinds are used extensively in computer andcomputer system components, digital processing systems and the like.Such memories can be formed, to considerable advantage, based on thestorage of digital bits as alternative states of magnetization ofmagnetic materials in each memory cell, typically thin-film materials.These films may be thin ferromagnetic films having information storedtherein based on the direction of the magnetization occurring in thosefilms. The information is typically obtained either by inductive sensingto determine the magnetization state, or by magneto-resistive sensing ofeach state.

Such ferromagnetic thin-film memories may be conveniently provided onthe surface of a monolithic integrated circuit to thereby provide easyelectrical interconnection between the memory cells and the memoryoperating circuitry on the monolithic integrated circuit. When soprovided, it is desirable to reduce the size and increase the packingdensity of the ferromagnetic thin-film memory cells to achieve asignificant density of stored digital bits.

Typically, a thin-film magnetic memory includes a number of sense linesintersected by a number of word lines. At each intersection, a thin filmof magnetically coercive material is provided. The magnetic materialforms a magnetic memory cell in which a bit of information is stored. Anumber of digital lines may also be provided. The digital linestypically extend parallel to the sense lines, and are used to initiallyhelp rotate the magnetic field vector of the memory cells during, forexample, a write operation. This initial rotation of the magnetic fieldvector increases the torque that can be applied by the word line fieldduring a write operation. Typically, both the digital line and the wordline must be asserted to write a corresponding magnetic bit within thememory. Therefore, the digital line can be used to select whether a reador a write operation is performed. For example, when only the word lineis asserted, a read operation is performed. When both the word line anddigital line are asserted, then a write operation is performed.

A number of competing factors influence the packing density that can beachieved in a typical memory. One factor is the width and thickness ofthe word lines, and where applicable, digital lines. The dimensions ofthe word lines and digital lines must typically decrease with increasedpacking density. Reducing the dimensions of the word lines and digitallines, however, tends to reduce the current that can be accommodatedthereby, and thus the magnetic field that can be produced at thecorresponding magnetic bit regions.

Another factor is the distance between the word lines and, whereapplicable, digital lines, and thus the distance between a word lineand/or digital line and an adjacent memory cell. Typically, the distancebetween the word lines and the digital lines must decrease withincreased packing density. However, this increases the likelihood thatthe magnetic field produced by one word line or digital line mayadversely affect the information stored in an adjacent memory cell. Thisadverse interaction is often called cross-talk.

Since a magnetic memory operates with internally generated magneticfields from word, sense, and digital lines, it is desirable to shield itfrom externally generated low frequency magnetic fields as well as EMI.One way to reduce the effects of externally generated fields on thinfilm magnetic memories is to provide a shield in the package that housesthe memory. Shielded packages typically have a cavity for receiving thethin-film magnetic memory. A lower shielding layer is provided below thecavity, and an upper shielding layer is provided above the cavity, suchas in or on the package lid. The upper and lower shielding layers areoften formed from Mu metal or the like. In this configuration, the upperand lower shielding layers may help shunt externally generated fields,limiting their influence on the thin-film magnetic memory.

A limitation of using shielded packages is that the shielding layers maynot protect the magnetic bits from internally generated fields, such asthose produced by adjacent word or digital lines or the like. Instead,the upper and lower shielding layers of the package may actuallyincrease or concentrate the internally generated fields at the magneticbit in much the same way as a word line keeper increases or concentratesthe magnetic field produced by a word line at the magnetic bit.

U.S. Pat. No. 5,039,655 to Pisharody discloses one approach for reducinginternally generated noise, and more particularly, for reducingcross-talk between word lines and adjacent magnetic bits. In Pisharody,a magnetic field keeper formed from a superconductor material isprovided around at least three sides of each word line. Pisharody statesthat the superconductor material shunts the magnetic fields generated bythe adjacent word lines, thereby reducing the effects on adjacent memorycells.

A limitation of Pisharody is that only one side of each memory cell hasa superconducting magnetic field keeper. Thus, the other side of eachmemory cell is left completely unprotected from stray fields. As such,magnetic fields that enter the memory from the non-word line side arenot suppressed by the superconducting layer. Rather, the superconductinglayer may actually increase or concentrate the fields at the magneticbit regions in much the same way as a word line keeper increases orconcentrates the magnetic field produced by a word line at the magneticbit.

What would be desirable, therefore, is a monolithically formed thin-filmmagnetic memory that has local shielding on both sides of a magnetic bitto help protect the magnetic bit from external EMI, internally generatedcross-talk, and other internally and externally generated noise.

SUMMARY OF THE INVENTION

The present invention overcomes many of the disadvantages of the priorart by providing a monolithically formed ferromagnetic thin-film memorythat has local shielding on at least two sides of a magnetic bit region.The local shielding helps protect the magnetic bit from externallygenerated EMI, internally generated cross-talk, and other internally andexternally generated noise. In addition, when the local shielding layersare provided adjacent a word line and/or digital line, the localshielding layers may help concentrate the magnetic fields of the wordlines and/or digital lines at the magnetic bit regions, in much the sameway as a magnetic field keeper. Accordingly, the shielding layers maynot only help reduce undesirable fields from influencing the magneticbit regions, but may also enhance the desirable magnetic fields at themagnetic bit regions.

In one illustrative embodiment, top and bottom shielding layers areprovided above and below a conventional monolithically formedmagneto-resistive memory element, although it is contemplated that anytype of magnetic memory element may be used. The memory element ispreferably formed on the underlayers of a conventional monolithicintegrated circuit. This helps provide easy electrical interconnectionbetween the memory cells and the memory operating circuitry on themonolithic integrated circuit. The shielding layers are also preferablymonolithically formed.

In another illustrative embodiment, a word line is provided adjacent thememory elements, with a first shielding layer extending adjacent theword line. A second shielding layer is provided adjacent a digital line,which preferably extends along the other side of the memory elements. Tohelp reduce internally generated cross-talk, the first and/or secondshielding layers may extend along the side surfaces of the word lineand/or digital line, respectively. As indicated above, this may enhancethe desired magnetic fields at the memory element and reduce cross-talk.

To fabricate a preferred embodiment of the present invention, a baseinsulating layer is first provided over the underlayers of a monolithicintegrated circuit. A cavity is then formed in the base insulatinglayer, wherein the cavity has a bottom surface and two spaced sidesurfaces. A lower shielding layer and a lower barrier layer are providedon the bottom and/or side surfaces of the cavity. A lower conductivematerial layer is then provided in the cavity and above the softmagnetic material layer and the barrier layer to substantially fill thecavity. The lower conductive material layer forms the word linestructure.

A lower insulating layer is then provided over the word line structure.A magnetic bit region is formed on the lower insulating layer. An upperinsulating layer is provided over the magnetic bit region. When adigital line is used, a conductive material layer is provided on theupper insulating layer, which is then patterned using conventionalpatterning techniques. A barrier layer can then be provided, followed byan upper shielding layer. The upper shielding layer may be providedalong the top and/or sides of the digital line using conventionalprocessing techniques. When no digital line is desired, the uppershielding layer may be applied directly to the upper insulating layer,if desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects of the present invention and many of the attendantadvantages of the present invention will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, in which like reference numerals designate like partsthroughout the figures thereof and wherein:

FIG. 1 is a cross section of a monolithically formed memory elementhaving an upper shield and a lower shield;

FIG. 2 is a cross section of a monolithically formed memory elementhaving an upper shield and a lower shield, with a word line positionedbetween the memory element and the lower shield;

FIG. 3 is a cross section of a monolithically formed memory elementhaving an upper shield and a lower shield, with a word line positionedbetween the memory element and the lower shield and a digital linepositioned between the memory element and the upper shield;

FIGS. 4-18 illustrate a preferred method for forming a monolithic memoryelement with upper and lower shielding elements;

FIG. 4 a cross section of an insulating layer, preferably provided onconventional integrated circuit underlayers;

FIG. 5 is a cross section of the insulating layer of FIG. 4 with apatterned photoresist provided on the top surface thereof;

FIG. 6 is a cross section of the insulating layer of FIG. 5 after acavity is etched therein, and after the patterned photoresist isremoved;

FIG. 7 is a cross section of the insulating layer and cavity of FIG. 6with the soft magnetic material layer deposited on the bottom surface ofthe cavity;

FIG. 8 is a cross section of the insulating layer and soft magneticmaterial layer of FIG. 7 with the conductive material layer depositedthereon;

FIG. 9 is a cross section of the insulating layer, soft magneticmaterial layer and conductive material layer of FIG. 7 with thoseportions that are above the top surface of the insulating layer removed;

FIG. 10 is a cross section of the insulating layer, soft magneticmaterial layer and conductive material layer of FIG. 9 with a thininsulating layer deposited thereon;

FIG. 11 is a cross section of the insulating layer, soft magneticmaterial layer, conductive material layer and thin insulating layer ofFIG. 10 after the magnetic material is deposited and patterned thereon;

FIG. 12 is a cross section of the insulating layer and cavity of FIG. 6with the soft magnetic material layer deposited on the bottom and sidesurfaces of the cavity;

FIG. 13 is a cross section of the insulating layer and soft magneticmaterial layer of FIG. 12 with the conductive material layer depositedthereon;

FIG. 14 is a cross section of the insulating layer, soft magneticmaterial layer and conductive material layer of FIG. 13 with thoseportions that are above the top surface of the insulating layer removed;

FIG. 15 is a cross section of the insulating layer, soft magneticmaterial layer and conductive material layer of FIG. 14 with a thininsulating layer deposited thereon;

FIG. 16 is a cross section of the insulating layer, soft magneticmaterial layer, conductive material layer and thin insulating layer ofFIG. 15 after the magnetic bit region is deposited and patternedthereon;

FIG. 17 is a cross section of the insulating layer, soft magneticmaterial layer, conductive material layer, thin insulating layer, andmagnetic bit region of FIG. 16, with another conductive material layerand another soft magnetic material layer deposited thereon;

FIG. 18 is a cross section of the embodiment of FIG. 17 taken alonglines 18-18;

FIG. 19 is a schematic diagram showing an illustrative magnetic fieldproduced by a word line or digital line with no magnetic field keeper;

FIG. 20 is a schematic diagram showing an illustrative magnetic fieldproduced by a word line or digital line with a magnetic field keeperextending along one side thereof; and

FIG. 21 is a schematic diagram showing an illustrative magnetic fieldproduced by a word line or digital line with a magnetic field keeperextending along the underside and side walls thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a cross section of a monolithic memory element that has anupper shield and a lower shield. The upper shield 10 is provided abovememory element 14, and lower shield 12 is provided below memory element14. It is contemplated that any type of magnetic memory element 14 maybe used.

The memory element 14 is preferably formed above the underlayers of aconventional integrated circuit. This helps provide easy electricalinterconnection between the memory cells and the memory operatingcircuitry on the monolithic integrated circuit. The shielding elements10 and 12 are also preferably monolithically formed with the integratedcircuit and the memory element 14.

The dots at 16 b and 16 c indicate that one or more layers may beinterposed between the memory element 14 and the upper and lower shieldelements 10 and 12, respectively. In the embodiment shown, all that isimportant is that at least two sides, such as the upper and lower sidesof the memory element 14, are cladded with two shielding elements 10 and12. Dots 16 a indicate that one or more layers may be provided above theupper shield element 10, and dots 16 d indicate that one or more layersmay be provided below lower shield 12.

To provide a selection mechanism to the memory, a word line may beprovided adjacent each memory element. For example, FIG. 2 shows a crosssection of a memory element 18 with cladding upper and lower shieldingelements 20 and 22, with a word line 24 positioned between the memoryelement 18 and the lower shield 22. It is recognized that the word line24 may be positioned between the memory element 18 and the upper shield20, if desired. The lower shield 22 is preferably positioned adjacentthe word line 24 along the side 26 of the word line 24 that is away fromthe memory element 18.

The dots at 30 b indicate that one or more layers may be interposedbetween the memory element 18 and the upper shield element 20. Likewise,dots 30 c indicate that one or more layers may be interposed between theword line 24 and the lower shield element 22. Dots 30 a indicate thatone or more layers may be provided above the upper shield element 20,and dots 30 d indicate that one or more layers may be provided belowlower shield 22. Finally, dots 30 e indicate that one or more layers maybe provided between the word line 24 and the memory element 18.

As indicated above, some memories include a number of digital lines thatextend generally parallel to the sense lines, and generallyperpendicular to the number of word lines. The digital lines may be usedto help initiate rotation of the magnetic field vector of the magneticelement during, for example, a write operation. The initial rotation ofthe magnetic field vector increases the torque that can be applied bythe word line field during a write operation.

FIG. 3 is a cross section of a memory element 36 with cladding upper andlower shielding elements 38 and 40, with a word line 42 positionedbetween the memory element 36 and the lower shield 40 and a digital line44 positioned between the memory element 36 and the upper shield 38.This configuration is only illustrative, and it is contemplated that theword line 42 may be positioned, for example, above the memory element36, and the digital line 44 may be positioned below the memory element36.

In this configuration, the local shielding elements 38 and 40 may helpprotect the memory element 36 from externally generated EMI, and mayfurther help concentrate the magnetic fields produced by the word line42 and digital line 44 to the memory element 36. Accordingly, theshielding layers may not only help reduce undesirable fields frominfluencing the magnetic bit regions, but may also help enhance thedesired magnetic fields at the memory element 36.

FIGS. 4-18 illustrate a preferred method for forming an illustrativemonolithic memory element with upper and lower shields. FIG. 4 is across section of an insulating layer 110 such as silicon nitride orsilicon oxide, preferably formed on conventional integrated circuitunderlayers 112. The underlayers 112 may include, for example, allcircuit layers for a conventional CMOS wafer up to the metal layers. Theunderlayers 112 are shown using a dashed line, and are not included inthe subsequent figures for clarity.

To form a cavity in the insulating layer 110, a photoresist layer 114 isprovided on the top surface 116 of the insulating layer 110. Thephotoresist layer 114 is patterned in a conventional manner toselectively remove a portion 118 of the photoresist layer 114 whichoverlays the desired cavity, as shown in FIG. 5. The exposed portion ofthe insulating layer 110 is then etched using a conventional etchingprocess to form cavity 120 as shown in FIG. 6. The cavity 120 has abottom surface 122 and two spaced side surfaces 124 a and 124 b. Thephotoresist is subsequently removed.

FIG. 7 is a cross section of the insulating layer 110 and cavity 120 ofFIG. 6, with a soft magnetic material layer 130 deposited thereon. Inthe illustrative embodiment, the deposition of the soft magneticmaterial layer 130 only occurs on the horizontal surfaces of theinsulating layer 110, including the bottom surface 122 of the cavity120, and the remaining top surface 132 of the insulating layer 110. Ascan be seen, the soft magnetic material layer 130 preferably onlypartially fills the cavity 120.

The soft magnetic material layer 130 may include a first barrier layer136, a second barrier layer 138 and a soft magnetic material 130therebetween. The first and second barrier layers are preferably madefrom Ta, TiW, TiN, TaN, SiN, SiO₂, or similar material. The softmagnetic material is preferably formed from NiFe, NiFeCo, CoFe, or othersimilar material having soft magnetic properties. It is contemplatedthat the first barrier layer 136, the second barrier layer 138 and softmagnetic material 130 may be deposited during a single conventionaldeposition process step, as is known in the art.

After the soft magnetic material layer 130 is deposited, a conductivematerial layer 150 is deposited on the top surface of the soft magneticfield layer 130. The conductive material layer 150 is deposited to atleast substantially fill the cavity 120, and preferably covers theentire wafer including those portions of the soft magnetic materiallayer 130 that lie outside of the cavity 120 as shown in FIG. 8.Conductive material layer 150 is preferably formed from Cu or AlCu. Ascan be seen, the conductive material layer 150 is self-aligned with thesoft magnetic field layer 130.

It is contemplated that a number of contacts or vias may be providedbetween selected underlayers and/or metal lines before and after theconductive material layer 150 is deposited. In one embodiment, each ofthe contacts/vias are filled with tungsten to reduce the resultingcontact/via resistance. It is known that this may require relativelyhigh processing temperatures. However, and in accordance with co-pendingU.S. patent application Ser. No. 08/993,009, filed Dec. 18, 1997, andentitled “Self-Aligned Wordline Keeper and Method of ManufactureTherefor”, the contact and via processing may be performed before themagnetic materials are provided, thereby preserving the magneticproperties of the magnetic materials.

As can be seen, portions of the soft magnetic material layer 130 andconductive material layer 150 may lie above the top surface 132 of theinsulating layer 110. In a preferred embodiment, these portions may beremoved using a mechanical or chemical-mechanical polishing (CMP)process. FIG. 9 is a cross section showing the insulating layer 110, thesoft magnetic material layer 130, and the conductive material layer 150after the polishing step is completed.

Polishing the top surface of the insulating layer to remove thoseportions of the soft magnetic material layer 130 and conductive materiallayer 150 that lie above the top surface of the insulating layer 110provides a number of advantages. First, a relatively planer top surfaceis provided. This allows the deposition of a relatively thin insulatinglayer 160 as shown in FIG. 10, which increases the magnetic fieldproduced by the conductive material layer 150 at bit region 170. Second,the conductive material layer 150 may be made from any type of materialsince mechanical and chemical-mechanical polishing are typicallynon-selective. Deposition/photoresist/etch processes typically arelimited to the types of metals that can be used.

After polishing, a thin insulating layer 160 is preferably provided onthe top surface of the insulating layer 110, and over the cavity 120, asshown in FIG. 10. A magnetic bit region 170 may then be deposited andpatterned on the thin insulating layer 160 as shown in FIG. 11.

Bit region 170 may be a sandwich-type structure similar to thatdisclosed in commonly assigned U.S. Pat. No. 4,780,848 to Daughton etal., which is incorporated herein by reference. As further described inDaughton et al., bit region 170 may include a silicon nitride diffusionbarrier layer of approximately 300 angstroms. A first layer of a 65% Ni,15% Fe, and 20% Co Permalloy of 150 angstroms or less is then deposited.Next, a non-magnetic intermediate layer, such as TaN or Cu, is depositedto a thickness of 50 angstroms or less. Then a second layer of aPermalloy is deposited to a thickness of 150 angstroms or less. This isfollowed by depositing a second non-magnetic resistive layer of tantalumnitride or tantalum to a thickness of 50-1000 angstroms. A capping, oretch stop, layer of Chromium silicon (CrSi) is then deposited to athickness in the range of 100 to 1500 angstroms. All of the depositionsof bit region 170 are preferably done in-situ. The deposition of thePermalloy layers are done in the presence of a bias magnetic field.

FIG. 12 shows an alternative embodiment of the present invention wherethe soft magnetic material layer 180 is deposited on the bottom 122 andside surfaces 124 a and 124 b of the cavity 120. This can beaccomplished by using a deposition process that covers both horizontaland vertical surfaces of insulating layer 110, as is known in the art.The remaining fabrication steps shown in FIGS. 13-16 are similar tothose described above with reference to FIGS. 8-11, respectively.

The preferred embodiment preferably includes a number of digital linesextending generally perpendicular to the word lines. The digital linesare used to help initiate rotation of the magnetic field vector of themagnetic bit region during, for example, a write operation. This initialrotation of the magnetic field vector increases the torque that can beapplied by the word line field during the write operation.

To form the digital line, an insulating layer 184 is first provided overthe memory element 170, as shown in FIG. 17. A conductive material layer186 is then provided on insulating layer 184, which is then patternedusing conventional patterning techniques. A shielding element 188 isthen provided over the conductive material layer 186. It is contemplatedthat the shielding element 188 may include one or more barrier layers,as described above.

Preferably, the shielding element 186 extends along the top and sidewalls of the digital line 186, as more clearly shown in FIG. 18. Byincluding the shielding element 186 on the side walls as shown, theeffect of the magnetic fields produced by adjacent digital lines onadjacent memory elements may be reduced. If no digital line is desired,shielding element 188 may be applied directly to the upper insulatinglayer 184.

FIG. 19 is a schematic diagram showing an illustrative magnetic fieldproduced by a word line or digital line 200 with no shield. The wordline or digital line 200 is carrying a current into the page to producea magnetic field 202. The magnetic field 202 is shown extendingsymmetrically around word line or digital line 200 and intersecting abit region 204.

FIG. 20 is a schematic diagram showing an illustrative magnetic fieldproduced by a word line or digital line 210 with a shield 212 adjacentthe bottom surface 214 thereof. Upon application of current in the wordline or digital line 210, the soft magnetic material in shield 212aligns as shown, and helps concentrate the magnetic field 218 above theword line or digital line 210. This helps increase the magnetic field218 at a bit region 216.

FIG. 21 is a schematic diagram showing an illustrative magnetic fieldproduced by a word line or digital line 220 with a magnetic field keeper222 adjacent the bottom surface 224 and side walls 226 a and 226 bthereof. Upon application of current in the word line or digital line220, the soft magnetic material in shield 222 aligns as shown. Byproviding a shielding element on the side walls 226 a and 226 b, themagnetic field 230 is even more effectively concentrated adjacent theword line or digital line 220, thereby further increasing the magneticfield 230 at a bit region 232.

In addition to helping concentrate the word line and digital linefields, the shielding elements may help shunt any externally generatedfields from reaching the thin-film magnetic memory. This may reduce thesensitivity of the memory elements to external fields, which mayincrease the reliability of the device.

It is contemplated that the upper and lower shields of the presentinvention may also be used in conjunction with magnetic field sensordevices. Magnetic field sensor devices often include a magneto-resistivematerial in the sensor element. Generally, by measuring the resistancechange of the magneto-resistive material, the magnitude of the incidentmagnetic field can be determined. The shielding elements of the presentinvention may improve the performance of these sensor devices.

In most cases, the magneto-resistive material has edge domains that aremagnetized in a particular direction, regardless of whether the incidentmagnetic field is applied. Under some circumstances, the direction ofthe magnetization field in one or more of the edge domains can becomereversed. This can happen, for example, when the incident magnetic fieldexceeds a maximum threshold. Under these circumstances, the edge domainstypically must be reset before the magnetic field sensor can resumenormal operation. The edge domains are typically reset using a resetline that is placed adjacent to the magnetic field sensor. Accordingly,it is contemplated that a reset line of a magnetic field sensor devicemay include the above-described magnetic shield elements on either sidethereof to increase the magnetic field produced by the reset line at themagnetic material of the sensor device, and to reduce the effects ofexternally generated fields.

Having thus described the preferred embodiments of the presentinvention, those of skill in the art will readily appreciate that theteachings found herein may be applied to yet other embodiments withinthe scope of the claims hereto attached.

1. A method for monolithically forming a ferromagnetic thin film memoryelement, comprising: forming a lower shielding layer using a softmagnetic material; forming a magnetic storage means above the lowershielding layer; forming an upper shielding layer using a soft magneticmaterial above said magnetic storage means; and said lower shieldinglayer, said upper shielding layer and said magnetic storage means allmonolithically formed on a common substrate.
 2. A method according toclaim 1, further comprising forming a first conductive layer betweensaid lower shielding layer and said magnetic storage means.
 3. A methodaccording to claim 2, further comprising forming a second conductivelayer between said upper shielding layer and said magnetic storagemeans.
 4. A method according to claim 3, further comprising forming afirst barrier layer between said lower shielding layer and said firstconductive layer.
 5. A method according to claim 4, further comprisingforming a second barrier layer between said upper shielding layer andsaid second conductive layer.
 6. A method according to claim 3, whereinsaid first conductive layer functions as a word line.
 7. A methodaccording to claim 6, wherein said second conductive layer functions asa digital line.
 8. A method of forming a ferromagnetic thin film memoryelement having an upper magnetic field shield and a lower magnetic fieldshield, the method comprising: providing an insulating layer; forming acavity in said insulating layer, wherein the cavity has a bottom surfaceand two spaced side surfaces; providing a first soft magnetic materiallayer above the bottom surface of the cavity, thereby partially fillingthe cavity; providing a first conductive layer in the cavity and abovethe first soft magnetic material layer to at least substantially fillthe cavity; providing a first insulating layer over the first conductivematerial layer; forming a magneto-resistive bit region above said firstinsulating layer; providing a second insulating layer above saidmagneto-resistive bit region; providing a second conductive materiallayer above the second insulating layer; and providing a second softmagnetic material layer above the upper surface of the second conductivematerial layer.
 9. A method according to claim 8, wherein said firstsoft magnetic material layer is provided on both the bottom surface andat least part of the side surfaces of the cavity.
 10. A method accordingto claim 8, wherein said second conductive material layer has an uppersurface, a lower surface, and two spaced side surfaces, wherein thesecond soft magnetic material layer substantially covers the uppersurface and the two spaced side surfaces of the second conductivematerial layer.
 11. A method according to claim 8, further comprisingproviding a first barrier layer on said first soft magnetic layer beforeproviding said first conductive layer in the cavity.
 12. A methodaccording to claim 11, further comprising providing a second barrierlayer on the upper surface of the second conductive material layerbefore providing said second soft magnetic material layer.
 13. A methodfor monolithically forming a ferromagnetic thin film memory element,comprising: forming a first magnetic shielding layer; forming a firstbarrier layer above the first magnetic shielding layer; forming a firstconductive layer above the first magnetic shielding layer such that thefirst barrier layer is disposed between the first magnetic shieldinglayer and the first conductive layer; forming a magnetic storage cellabove the first conductive layer such that the first conductive layer isdisposed between the first magnetic shielding layer and the magneticstorage cell; forming a second conductive layer above the magneticstorage cell such that the magnetic storage cell is disposed between thefirst conductive layer and the second conductive layer; forming a secondbarrier layer above the second conductive layer such that the secondconductive layer is disposed between the magnetic storage cell and thesecond barrier layer; and forming a second magnetic shielding layerabove the second conductive layer such that the second barrier layer isdisposed between the second conductive layer and the second magneticshielding layer.
 14. The method as defined in claim 13, furthercomprising forming the first barrier layer from tantalum (Ta).
 15. Themethod as defined in claim 13, further comprising forming the firstbarrier layer from titanium-tungsten (TiW).
 16. The method as defined inclaim 13, further comprising forming the first barrier layer fromtitanium-nitride (TiN)
 17. The method as defined in claim 13, furthercomprising forming the first barrier layer from tantalum nitride (TaN).18. The method as defined in claim 13, further comprising forming thefirst barrier layer from silicon nitride (SiN).
 19. The method asdefined in claim 13, further comprising forming the first barrier layerfrom silicon dioxide (SiO₂).
 20. The method as defined in claim 13,further comprising forming the first magnetic shielding layer from NiFe,NiFeCo, or CoFe.